Electronic engraving machine



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ELECTRONIC ENGHAVING MCHlNE Filed DGL 2,2, 1953 u 3l INVENTORS:

* 3' lfacfnldawd {Ns/dela. f BY @hay me United States Patent O ELECTRONIC ENGRAVING MACHINE Yoshihiro Machida, Shugakuin, Sakyo-ku, and Fumihiko Nishida, Nishi-iru, Kamikyo-ku, Kyoto, Japan, assignors to Dainippon Screen Seizo Kabuishiki Kasha (Dainippon Screen Mfg. Co., Ltd.), Kyoto, Japan Filed Oct. 22, 1963, Ser. No. 318,007 3 Claims. (Cl. 74-110) This invention relates to an electronic engraving machine With continuously variable reproduction scale, and more particularly to machines of this type wherein two tables carry the original picture to be reproduced and a printing plate material, respectively, a scanning head for scanning the original picture and an engraving head for engraving the printing plate material being advanced on the above tables in Ia direction perpendicular to the direction of reciprocating motion of said tables.

A successful type of the two-table machine has been developed by Dr. Hell as shown and'described in U.S. Patent No. 2,986,598. In such machine, the copy table and the engraving table are coupled by a somewhat heavy slide through operating levers which engage lthe tables with their upper end and have the lower journalled .to structural parts of the machine, with the respective middle portions of the levers rotatably and adjustably connected to the slide. According to thismachine, one of the operating levers is restricted to enlarge the machine and the other lever is used for reduction.

An object of the present invention is the provision of an improved lever mechanism in a two-table type electronic engraving machine with a continuously variable reproduction scale.

Other objects of the invention will become apparent in the course of the following specication.

ln the accomplishment of the objectives of che present invention it was found advisable to provide a lever mechanism which comprises a lever rotatably journalled at its upper end to the engraving table, a lever rotatably journalled at its upper` end to the copy table, pivots for rotatably journalling the middle portions of these two levers to structural parts of the machine, a connecting rod which is constrained so as to reciprocate longitudinally and which has at its ends pins engaging in slots at the free ends of the respective levers, and means shifting the turning axis of either lever in a ldirection normal to the direction of movement of the connecting rod so as to produce a reciprocating motion of the two tables in accordance with the desired reproduction scale. The connecting rod may serve as the driving means for the lever mechanism.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawing showing by way of example, preferred embodiments of the inventive idea.

`FIG. 1 is a perspective view of essential parts of a machine constructed .in accordance with the principle of the invention;

FIG. 2 is a diagram to explain the kinematic operation of the leve-r mechanism; .and

FIG. 3 is a view similar to FIG. l, but showing a somewhat modified form of construct-ion.

The same reference numerals are applied to corresponding parts in these two embodiments.

Referring first to FIG. 1, reference numeral desice lignates a horizontally disposed engraving table mounted and guided by rails 11 and 12 for reciprocating motion. Numeral 13 indicates lche printing plate mate-rial which is to jbe engraved by an engraving head 14.

An original copy 15 is carried by a copy table 16 mounted and guided by -rails 17 and 18 for reciprocating motion. Numeral 19 indicates the scanning head electrically connected with the engraving head 14 which has a known engraving tool or stylus (not shown), which stylus is controlled, by said scanning head 19, its up and down motion in yaccordance with the brightness of the original copy 15. j

The reciprocating motion of the engraving table 10 is eiected by driving an electric motor 20. The drive of the motor 201 is transmitted, through a reversing device 21, to a screw threaded spindle 22 which engages with a nut 23 fastened to an edge of the engraving table 10. The reversing device 21 is controlled by an electric signal produced when the stylus comes to an end of the printing plate material 13, so that the reciprocation of the engraving table 10 is eifected by reversing the direction of rotation of the screw threaded spindle 22.

The nut 23 carries a stub shaft 24 to which is pivotally connected the upper end of a lever 25. At the lower end portion of the lever 25 is formed a longitudinal slot 26. The slot 26 receives the pin 27 at an end of a reciprocatin-g rod 28 which is constrained by guides 29 and 30 to a horizontal reciprocating motion in the longitudinal direction thereof. The other end of the reciprocating rod 28 is provided with a pin 31.

The copy table 16 carries, at a side thereof, also a stub shaft 32 to which is pivoted the upper end of a lever 33. The lower end portion of the lever 33 is provided with a longitudinal slot 34 into which enters the pin 32 of the reciprocating rod 28 mentioned above.

While, the levers 25 `and 33 are provided at their middle portions with longitudinal slots 35 and 36, respect-ively, the `slot 36 of the lever 33 receives a pivot or pin 37 extending from a structural part ofthe machine.

The slot 35 of the lever 25 also receives a pivot or pin 38. The pivot 38 is so constructed that it is capable of having its position shifted in a direction normal to the direction of movement of the rod 28. Thus a structural part of the machine is provided with -a scale plate 39 having a vertically extending slot 40 along which the reproduction ratio is marked. The pivot 38 can be adjusted in its position along the slot 40 provided with the scale and can be ixed in any adjusted position by means of a fastening member 41 which clamps the pivot 38 to the structural part of the machine. The adjustment or setting of the reproduction scale is effected by shifting the pivot 38 upwardly or downwardly along the slots 35 and 40. When the adjusting pivot 38 is set at the lower-most position, the picture on the copy table 16 will be enlarged to the maximum of the capacity of the machine. On the other hand, la minimum reduction takes place when the adjusting pivot 38 is placed in the upper-most position.

As illustrated above, the engraving table 1() and the copy table 16 are coupled by two levers 25 and 33 through the rod 28. That is to say, if the engraving table 10 moves for a certain distance there is produced a couple to turn the lever 25 about its axis 38. This couple is transmitted, through the rod 28, to another lever 33 as a moment to turn said lever 33 about the axis 37. Then, the copy table, which is pivoted at 32 to the lever 33,

moves in the same direction as that of the engraving table 10, The rate of movement of the copy table 16 resulting from turning of the lever 33 will depend, in case its turning pin 37 is xed, on the internal division ratio of the lever 25.

Referring now more speciically to FIG. 2, which illustrates kinematically the lever mechanism of the present invention, the vertical distance between shaft 24 and pivot 38 of the lever 25 is assumed to be a, and the vertical distance between pivot 38 and pin 27 is assumed to be b. Similarly, the vertical distance between lshaft 32 and pivot 37 of the lever 33 is 4assumed to be c, and the vertical distance between pivot 37 and pin 31 is assumed to be d. And, the movement of the engraving table 10 is represented by x from the point 24 to 24', `and similarly, the movement of the copy table 16 is represente-d by y from the point 32 to 32'. Let the distance of respective movement of the lower ends 27 and 31 of the levers 25 and 33 be represented by u and v, respectively, then a c 5u, and y-v Since the pins 27 and 31 are connected to each other by means of the rod 28,

Therefore,

Lai y b c Assumed that the turning .axis of the lever 33 is xed at 37, that is, that d/c is constant, and when the turning axis of the lever 25 is adjusted and xed at 38, that is, a/b is made constant, the ratio x/y will be constant independent of the rotation of the levers. Then, the movement of both tables and 16 is in proportions. This means that, if the ratio a/ b changed by shifting the pivot 38, the ratio x/y will be changed accordingly.

In operation of the machine, the stroke ratio of the engraving head 14 and the scanning head 19 is adjusted to the ratio corresponding to of the above-mentioned levers 25 and 33. Assumed that then there will result a reduction on the printing plate 13 as compared with the original copy 15. When -an enlargement will be obtained. In principle, the ratio X/y will be changed from infinitesimal to infinity, by shifting the .position of the turning .pivot 38. Due to the mechanical condition, however, the reproduction ratio will be limited to a certain range.

In one embodiment of the machine, the turning axis or pivot 37 of the lever 33 is positioned midway between the lever ends 31 and 32, so that the distance of movement of the lower end at 27 of the lever 25 is same with that of the movement of the upper end 32 of the lever 33. However, the pivot 37 is so constructed that it is able to shift its ixing position, similarly to the pivot 38, between the upper and the lower ends of the lever 33. The reproduction scale is adjusted on the basis that when an equal size of reproduction is obtained FIG. 3 shows a modied form of construction of the machine, wherein the lever 25, the upper end of which is pivoted at 24 to the engraving table 10, has a fixed turning axis, While the scale plate 39 together with the reproduction adjusting pin 38 is associated with the lever 33, the upper end of which is pivoted at 32 to the copy table 16. The coupling of the levers 25 and 33 is effected by a piston rod 50. The piston rod 50 is provided with a piston 51 contained in a cylinder 52 which has two orifices connected with hydraulic lines 53 and 54 terminating in a hydraulic control device 55 for governing the feed and return of hydraulic uid so as to eiect reciprocation of the piston 51 and therewith rocking of two levers 25 and 33 as mentioned above. In this second form of construction, both levers 25 and 33 are driven directly at their respective lower end 27 and 31, so that the machine construction will be simple and it will improve the accuracy of reproduction. The driving of the lever mechanism is not, of course, limited to be such a hydraulic piston device. A screw threaded spindle such as shown in FIG. l can satisfactorily be used instead of the hydraulic piston.

What we claim is:

1. In a two-table type electronic eng-raving machine with continuously variable reproduction scale, a lever mechanism comprising a lever rotatably journalled at its upper end to an engraving table, a lever rotatably journailed at its upper end to a copy table, means rotatably journalling the middle portions of said two levers to structural parts of the machine, a connecting rod, means longitudinally reciprocating said connecting rod, pins carried' by the ends of said connecting rod and engaging in slots at the free ends of said levers, and means shifting the turning axis of either lever to produce the reciprocating motion of said two tables in accordance with the desired reproduction scale.

2. A two-table type electronic engraving machine as claimed in claim 1, in which the connecting rod is the driving shaft of the lever mechanism.

3. A two-table type electronic engraving machine in accordance with claim 1, wherein the means moving the connecting rod comprise a piston and a cylinder enclosing said piston.

References Cited by the Examiner UNITED STATES PATENTS 2,986,598 5/1961 Hell 178-6.6 3,109,059 10/1963 Kargl 178-6.6

MILTON KAUFMAN, Primary Examiner. 

1. IN A TWO-TABLE TYPE ELECTRONIC ENGRAVING MACHINE WITH CONTINUOUSLY VARIABLE REPRODUCTION SCALE, A LEVER MECHANISM COMPRISING A LEVER ROTATABLY JOURNALLED AT ITS UPPER END TO AN ENGRAVING TABLE, A LEVER ROTATABLY JOURNALLED AT ITS UPPER END TO A COPY TABLE, MEANS ROTATABLY JOURNALLING THE MIDDLE PORTIONS OF SAID TWO LEVERS TO STRUCTURAL PARTS OF THE MACHINE, A CONNECTING ROD, MEANS LONGITUDINALLY RECIPROCATING SAID CONNECTING ROD, PINS CARRIED BY THE ENDS OF SAID CONNECTING ROD AND ENGAGING IN SLOTS AT THE FREE ENDS OF SAID LEVERS, AND MEANS SHIFTING THE TURNING AXIS OF EITHER LEVER TO PRODUCE THE RECIPROCATING MOTION OF SAID TWO TABLES IN ACCORDANCE WITH THE DESIRED REPRODUCTION SCALE. 